Moistening means for duplicating machines



Aug. 13, 1957 Filed July 26, 1954 L. A. SMITZER 2,802,445

MOISTENING MEANS FOR DUPLICATING MACHINES 3 Sheets-Sheet l 3, 1957 L. A.SMITZER 2,802,445

MOISTENING MEANS FOR DUPLICATING MACHINES Fild July 28, 1954 3Sheets-Sheet 2 Aug. 13, 1957 A. SMITZER 2, 0

MOISTENING MEANS FOR DUPLICATING MACHINES Filed July 26, 1954 5Sheets-Sheet s United States Patent D MOISTENING MEANS FOR DUPLICATINGMACHINES Louis A. Smitzer, Chicago, Ill., assignor in Ditto,incorporated, Chicago, 111., a corporation of West Virginia ApplicationJuly 26, 1954, Serial No. 445,850

6 Claims. (Cl. 1l87ii) This invention relates to improvements inmoistening means for duplicating machines.

In duplicating machines of the type to which the present inventionrelates, the master sheet is carried on a rotating drum. A series ofcopy sheets are fed past the drum in pressure contact with the mastersheet wh ch carries the characters which are to be duplicated. In orderfor the duplicating action to take place, the surface of each copy sheetmust have been previously moistened.

In machines of this type, the copy sheets are forwarded to the drum,that is, to the bite of the drum and the pressure roll, by means of apair of feed rolls. In order to secure proper registration, these feedrolls are intermittently driven. Moisture is applied to the copy sheetby the upper feed roll. Consequently, the feed rolls serve the triplefunction of feeding, positioning and moistening.

In order to perform the moistening function, it is desired to apply athin film of liquid to the surface of the upper feed roll by suitablemeans. One such means comprises the combination of a spray means locatedabove the upper feed roll and wiper means of fibrous material in contactwith the feed roll which serves to distribute the fluid uniformly alongthe surface of the upper feed roll, this fluid often being referred toas a solvent. This arrangement has proved to be generally satisfactoryfor moistening a sheet which is of a width coextensive with the width ofthe feed rolls, since the amount of solvent supplied to the feed rollcan be regulated by adjusting the stroke of the pump which controls theaction of the spray means.

However, this arrangement is not entirely satisfactory if the copy sheetis substantially narrower than the roll for the reason that the film ofmoisture on those parts of the roll which are not contacted by the copysheet is not absorbed by the copy sheet. This has several undesirableresults.

In the first place, the fibrous material of the wiper tends to becomesaturated with the result that too much moisture is applied to thatportion of the feed roll which is contacted by the copy sheet due toside capillarity in the wiper.

In the second place, the solvent tends to collect in a bead along thebite of the upper and lower feed rolls; this bead will extend itselflaterally, particularly, when the feed rolls are stationary, with theresult that the leading edge of the next copy sheet will becomesaturated wtih thi head of solvent.

In the third place, the solvent tends to build up on the lower feed rollwith the result that the copy sheet will be moistened on theunder-surface. This is particularly evident when changing from a narrowto a wide copy sheet. This film of moisture on the under-surface of thecopy sheet will be transferred to the pressure roll, with the resultthat matter on the master sheet will become offset on the pressure roll,thus radically shortening the life of the master sheet. In the secondinstance where the leading edge is saturated, the master sheet may be2,802,445 Patented Aug. 13, 1957 crashed which means that the charactersof the master sheet are obliterated by blotting and running.

The foregoing undesirable features will occur irrespective of whetherthe duplicating action is of the solvent type, or of the reaction type,the former referred to a dissolving of the characters on the mastersheet and simultaneous transference of the dissolvable dye to the copysheet and the latter referring to a chemical reaction between the liquidor solvent and the matter from which the master sheet characters areformed.

It is an object of this invention to provide a combined feeding,positioning and moistening means which overcomes the above objections.

It is another object of this invention to provide, in combination with apair of intermittently rotating moistening rolls, means to remove theaccumulation of moistune from the bite thereof.

Still another object is to provide improved suction means for removingmoisture from the lower feed roll.

According to my invention, I provide, as a lower feed roll, a hollowporous roll which, due to its capillarity will rapidly absorb anyaccumulation of moisture at the bite, together with means formaintaining the interior of said feed roll at a sub-atmospheric pressureto the end that there will be a movement of liquid from the periphery ofthe roll to the hollow interior thereof.

Still another object is to provide, in moistening means of the typeindicated, a yielding supporting means for the lower feed roll incombination with a coupling between the lower feed roll and a pump whichwill not prevent up and down movement of the yieldingly supported roll.

Other features, objects, and advantages will become apparent as thedescription proceeds. 7

With reference now to the accompanying drawings in which like referencenumerals designate like parts:

Fig. l is a longitudinal sectional elevation through a duplicatingmachine showing a preferred embodiment of my invention;

Fig. 2 is a transverse vertical section taken along line 22 of Fig. I;

Fig. 3 is an enlarged vertical section, similar to Fig. 2, but showingcertain details of the construction of the feeding and moistening rolls;

Fig. 4 is a vertical section taken along line 4-4 of Fig. 3;

Fig. 5 is a plan section taken along line 5-5 of Fig. 3;

Fig. 6 is a vertical elevation taken along line 6-6 of Fig. 5; and

Fig. '7 is a detailed elevation of the leaf spring shown in Fig. 6.

With reference now to Figs. 1 and 2, the reference nomerals 10 and 11designate a pair of spaced side plates which are connected to each otherby a base member 12, and by other transverse structural members, notshown. Suitably journaled in the side plates 18 and 11 is a shaft 13upon which a drum 14 is mounted. Suitable means, not shown, are providedfor rotating the drum and drum shaft.

Located beneath the drum is a pressure roll 15 which is journaled inpivotally mounted cradles 16. Suitable means, not shown, are provided tomaintain the cradles 16 in such position that the pressure roll 15engages the drum with substantial pressure in order to provide thedesired duplicating action.

Disposed in front of the drum and pressure roll, which is to the left,as shown in Fig. 1, and in substantial alignment with the bite thereof.is a pair of combined feeding, positioning and moistening rolls 17 and18. The upper feed roll, as shown in Figs. 24, comprises an outerportion 19, formed of a comparatively resilient material, such as softrubber, soft neoprene, or other compliant rubber-like material and acore 20. The core is journaled in the side plates and 11 by suitablebearing units 21. The upper feed roll 17 is driven, through anoverrunning clutch unit 54 by suitable driving mechanism, not shown,which meshes with the gear 53, which is connected to the driving elementof the overrunning clutch unit 54.

The lower feed roll .18 comprises a hollow porous cylinder 22 which ismounted on a core 23 by means of rubber end members 24 in the form ofplugs which serve as spacers to maintain a concentric relationshipbetween the elements 22 and 23. Thus, a space 52 is provided within theinterior of the lower feed roll 18 in which the solvent can accumulate.

As shown in Fig. 3, one end of the core 23 is provided with a passageway25, the inner end of which communicates with intersecting bores 26, soas to provide communication between the space 52 and a suitable fitting,to be described hereinafter.

The extended and reduced ends of the core 23 are provided with bushings29 which rest in cradles 27 which are pivoted at 28. A suitable spring30 is provided which biases the cradles 27 in the counterclockwisedirection, as shown in Fig. 1, so that the lower feed roll 18 isyieldingly supported and held against the upper feed roll 17. Thisyielding support permits movement of the lower feed roll so as toaccommodate itself to copy sheets of various thickness which may be fedbetween the rolls 17 and 18, and it also permits the lower feed roll toaccommodate itself to any eccentricity of the surface of the hollowporous cylinder 22.

Means are provided for applying a thin film of moisture or solvent tothe surface of the upper feed roll 17 as it is rotated. This meansincludes a perforated spray tube 31 which, as shown in Figs. 1 and 2, islocated above the upper feed roll 17. A conduit 32 extends between theperforated spray tube 31 and a suitable pump 33, and the conduit 34extends between the pump 33 and a supply tank 35. In the particularembodiment shown, the tank is provided with a vented cap 36. Inoperation, the pump 33 is actuated by the rotation of the drum, onceeach revolution, so as to cause a measured amount of solvent to besprayed onto the upper feed roll 17 once during each drum revolution. Anexample of such pump is shown in Quirk Patent 2,659,303, dated November17, 1953.

In order to distribute the solvent uniformly over the roll andthroughout the operating cycle, a wiper 38 is provided which is mountedin suitable supporting means 39. The wiper is made of felt or othersuitable fibrous material and is held, by the supporting means 39, incontact with the upper feed roll 17, to the end that a film of solventof the desired thickness. may be applied to the surface of the upperfeed roll for transference to the surface of the copy sheets which arecontacted and fed thereby.

As pointed out above, any excess of liquid which collects on the lowerfeed roll 18 is absorbed by the porous material 22 from which the feedroll is made. and this liquid collects in the space 52. Means, shown inFigs 2 and 3, are provided to withdraw this liquid from the space 52 andto return it to the supply tank 35. Such means comprises a suction pump40 together with a conduit 41 extending from the pump to the supply tank35, at a point above the liquid level therein, and a conduit 42extending from the pump to a coupling in the form of a tube 43.

One end of the tube 43 is received within the passageway 25, and theother end is received within the conduit 42. The tube 43 is providedwith an enlarged central portion 44, against the inner end of which isdisposed a thrust Washer 45 and an O ring 46 of neoprene or the like.

A leaf spring 47 is secured by a screw 48 to the side plate 11 and bearsagainst the end of the portion 44 so that the O ring 46 will be confinedbetween the end surface of the core 23 and the thrust washer 45. Thus, ah

seal is provided which permits the core 23 to be rotated, withoutcausing rotation of the tube 43, and which seal maintains thesub-atmospheric pressure developedby the pump 40 within the passageway25, the tube 43, and the conduit 42.

As shown in Figs. 6 and '7, the leaf spring is provided with anon-circular opening 49 which conforms in shape to the slabbed end 50 ofthe enlarged portion 44. Thus, the leaf spring fits over the slabbed endand prevents the tube 43 from rotating. The tube 43 is easily removed byunscrewing the screw 48, which permits the tube 43 to be withdrawn fromthe passageway 25. Then the lower feed roll 18 can be lifted off of thecradles 27.

The tube 43 and its enlarged central portion 44 extend through anopening 51 formed in the side plate 11, this opening being sufficientlylarger than the dimensions of the central portion 44 as to permit thedesired up and down movement of the lower feed roll 18 and the cradles27. Thus, a coupling is provided between the lower feed roll 18 and theconduit 42 which permits both rotational and translational movement ofthe lower feed roll, since the conduit 42 is flexible.

In operation, the upper feed roll 17 is intermittently driven from thedrum 14 by suitable means, an example of which is shown and described inLevin Patent No. 2,661,686, dated December 8, 1953. The drum 14 may berotated either continuously or through a single cycle at a time,according to the type of operation desired.

The bite of the feed rolls 17 and 18, when the rolls are stationary,serve to position the leading edge of a copy sheet; then, when the feedrolls 17 and 18 commence their rotation, the copy sheet is fed to thebite of the drum 14 and pressure roll 15. Thereafter, it is notnecessary that the gear 53 be positively driven, because the overrunningclutch unit 54 permits the copy sheet to drive the feed rolls. The lowerfeed roll 18 is rotated by virtue of its pressure contact with the upperfeed roll 17.

Even though the copy sheet is considerably narrower than the width ofthe feed rolls 17 and 18, the moisture will not built up on the surfaceof the lower feed roll due to its porous nature. The suction pump 40 notonly serves to remove the liquid from the space 52, as it collectstherein, but it also, the pores having first been saturated, serves tomaintain the whole interior of the hollow porous cylinder 22 at asub-atmospheric pressure. This prevents dripping of the porous feed rolland also facilitates the dissipation and absorption of the bead ofliquid which might otherwise collect at the bite.

The suction pump may be actuated by the rotation of the drum in the samemanner as pump 33. Any type of pump may be suitable for the purpose ofcreating the desired suction, such as the bellows type of pump shown inthe aforesaid Quirk Patent No. 2,659,303, or a kneading tube type ofpump may be employed.

With reference to the leaf spring 47, it will be observed that the screw48 provides, in effect, a pivotal mounting for the leaf spring whichpermits a certain degree of up and down movement of the coupling tube 43with the lower feed roll 18, which feed roll can also be termed abacking roll for the upper feed roll 17.

Although the hollow porous cylinder 22 may be made from any one of anumber of ditferent porous materials, I have found that satisfactoryresults have been obtained by the use of a filter material of thealuminum oxide grain, ceramic bonded type. The desired porosity willdepend upon the nature of the liquid; for an alcohol base low surfacetension direct process solvent. I have found that a grade 20 filteroperates satisfactorily. This grade is stated by the manufacturer, TheCarborundurn Company, to have an average pore diameter of .010 inch.

For proper operation, the liquid should wet or fill the pores for theentire length of the roll, and for the entire 360 of the cylinder wall,in order to seal otf the pores so that the roll will hold the suction.When one starts with a dry roll, this condition can be obtained veryquickly if the porosity is fine enough as to provide capillarity in theaxial direction of the roll. If the pores are too large, this resultwill not be obtained as rapidly.

On the other hand, if the porosity is too fine, then the roll will notabsorb the liquid as rapidly as it would if the pores were larger.Therefore, there is an optimum porosity for different types of liquidsand pumps.

It is not necessary that a completely air tight seal be provided for thespace 52, that is, the interior of the porous roll. For instance, theremay be a certain amount of leakage through or around the elements 45 and46, and between the outer surface of tube 43 and the surface of thepassageway 25, without impairing the desired action. As a matter offact, a certain amount of air leakage may occur to replace the liquidwithdrawn. Also, there may be leakage between the members 24 and theircooperating parts. However, the leakage paths mentioned should alfordsufiicient resistance to the passage of air so that the desiredsub-atmospheric pressure within the space 52 may easily be maintained bythe suction pump 40 in order to prevent dripping from the lower half ofthe roll.

Although only a preferred embodiment of my invention has been shown anddescribed herein, it will be understood that various modifications andchanges may be shown without departing from the spirit of my inventionas pointed out in the appended claims.

I claim:

1. In a duplicating machine having a pair of side plates and amoistening roll journalled therein, the combination of a backing rolldisposed beneath said moistening roll, means for yieldingly supportingsaid backing roll for cooperation with said moistening roll, saidbacking roll comprising a hollow porous cylinder, a concentric innercore having end portions extending beyond said cylinder and journalledin said supporting means, and impervious end members spacing saidcylinder from said core and providing an enclosed chamber within saidcylinder, said core having an axial passageway in one of said endportions communicating at its inner end with said chamber, a coupling inthe form of a tube having one end received within said axial passageway,and having a central enlarged portion, sealing means confined betweensaid central enlarged portion and the end surface of said core, saidcoupling extending through an opening in said side frame, a leaf springmounted on said side frame and bearing against said coupling in an axialdirection in order to maintain the etfectiveness of said sealing means,said leaf spring having a portion at one end engaging said coupling torestrain the same against rotation with said backing roll, the other endbeing pivotally mounted on said side frame to permit up and downmovement of said backing roll with said supporting means.

2. In a duplicating machine having a pair of side plates and amoistening roll journalled therein, the combination of a backing rolldisposed beneath said moistening roll, means for yieldingly supportingsaid backing roll for cooperation with said moistening roll, saidbacking roll comprising a hollow porous cylinder having reduced endportions journalled in said supporting means, an axial passageway in oneof said end portions communicating at its inner end with the interior ofsaid cylinder, 3 coupling in the form of a tube having one end receivedwithin said axial passageway, and having a central enlarged portion,sealing means confined between said central enlarged portion and the endsurface of one of said reduced end portions, said coupling extendingthrough an opening in said side frame, and a leaf spring mounted on saidside frame and bearing against said coupling in an axial direction inorder to maintain the effectiveness of said sealing means, said leafspring also engaging said coupling to restrain the same against rotationwith said backing roll.

3. In a duplicating machine having a rotatable moistening roll, thecombination of a backing roll disposed beneath said moistening roll,means for yieldingly supporting said backing roll for cooperation withsaid moistening roll, said backing roll comprising a hollow porouscylinder, a concentric inner core having end portions extending belondsaid cylinder and journalled in said supporting means, and end membersspacing said cylinder from said core and providing an enclosed chamberwithin said cylinder, said core having an axial passageway in one ofsaid end portions communicating at its inner end with said chamber, acoupling in the form of a tube having one end received within said axialpassageway, means engaging said coupling to prevent the same fromrotating, sealing means between said coupling and said backing roll, anda source of sub-atmospheric pressure connected to said coupling.

4. Moistening means for a duplicating machine comprising a pair ofcooperating feeding and moistening rolls, means for applying a thin filmof liquid to the surface of one of said rolls, the other one of saidrolls being a hollow porous roll, said hollow porous roll comprising ahollow porous cylinder having openings of capillary dimensions aroundthe full 360 of its periphery, and end members cooperating with saidcylinder to provide an enclosed chamber bounded on 360 of its peripheryby a capillary wall, and suction means communicating with the interiorof said chamber and maintaining said interior at a subatmosphericpressure so that liquid which would otherwise accumulate at the bite ofsaid rolls will pass through said capillary wall into said chamber andaccumulate within said chamber, said accumulated liquid and thecapillary of said wall cooperating with each other to seal off saidcapillary openings in order to maintain said sub-atmospheric pressure,said suction means also serving to remove a portion of said accumulatedliquid from said chamber.

5. Moistening means as claimed in claim 4 in which said suction meanscomprises a suction pump, a conduit extending to said suction pump, acoupling connecting said conduit and said hollow porous roll, means toprevent said coupling from rotating, and sealing means between saidcoupling and said hollow porous roll.

6. Moistening means for a duplicating machine comprising a pair offeeding and moistening rolls positioned one above the other, means forapplying a thin film of liquid to the surface of the upper feed roll,the lower feed roll being a hollow porous roll, said hollow porous rollcomprising a hollow porous cylinder having openings of capillarydimensions around the full 360 of its pe riphery, and end memberscooperating with said cylinder to provide an enclosed chamber bounded on360 of its periphery by a capilllary wall, and suction meanscommunicating with the interior of said chamber and maintaining saidinterior at a sub-atmospheric pressure to cause liquid on the topsurface of said hollow porous roll to pass through said capillary wallinto said chamber and to accumulate within said chamber, said suctionmeans and said capillary wall cooperating with each other to preventaccumulated liquid within said chamber from flowing downwardly throughsaid capillary wall, said suction means also serving to remove a portionof said accumulated liquid from said chamber.

References Cited in the file of this patent UNITED STATES PATENTSWilderson Nov. 24, 1942

